(a) Field of the Invention:
This invention relates to a ceramics article adapted to be in sliding contact with an associated article during use (hereinafter referred to as a sliding contact type ceramics article) and a method for manufacturing the same.
(b) Description of the Prior Art:
In a rotary compressor for use in general in an air conditioner as shown in FIG. 1, a guide vane 3 is shown as being in sliding contact with a rotor 1 to divide the interior of a case 2. As shown also in FIG. 2, the guide vane 3 is plate-like in configuration and has a curved surface 3a in the direction of the thickness thereof at that end where it is in sliding contact with the rotor 1. The guide vane 3 has cutout 3b, 3b at the other end to receive a spring 4 to spring-urge the guide vane 3 in sliding contact with the rotor 1.
The guide vane for rotary compressors is conventionally formed using a molten metal. Recently, attempts have been made to mold the guide vane with the use of a ceramics material, since it is excellent in its heat-resistant and wear-resistant properties.
A conventional guide vane has been manufactured from the ceramics material by preparing a sintered body of simple configuration, such as a rectangular configuration and subjecting it to a grinding and a machining step to provide an article of the final configuration having a curved surface and cutouts.
However, the conventional method has drawbacks in that the grinding and machining steps for forming a simpler configuration into a complex configuration take lots of time and labor and involve a high manufacturing cost. In addition, the machined part of the guide vane such as a thinned part lowers its mechanical strength.
In the conventional method, a sliding-contact type ceramics article is formed to have a uniform density throughout, but has the following disadvantages:
(1) The high density and high wear-resistance cannot be attained at that part of the ceramics article which is in sliding contact with an associated article.
(2) The low density portion as opposed to the high density portion cannot be provided at that portion of the article where a lubricant should be retained to a greater extent.